1. Field of the Invention
The present invention relates generally to suspension systems for motorized vehicles, but more particularly to such suspension systems used to level the vehicle when transporting a heavy load.
2. Description of the Related Art
The art to which the invention relates includes motorized vehicle suspension systems and such systems used to level the body of a motorized vehicle when the vehicle transports or carries a heavy load.
The suspension systems comprising the art to which the invention relates are most commonly found in motorized vehicles such as pickup trucks and vans used to haul cargo, but may also be included in light or heavy duty trucks and automobiles. One such suspension system is the pneumatic shock absorber.
An advantage of a pneumatic shock absorber is the ability to control the body height of the vehicle, such as the bed height of a pickup truck, through the introduction of a pressurized gas such as air into the shock absorber which is interpositioned between the frame and the body of the vehicle. When pressurized, the length of the pneumatic shock increases and is able to adjust the relative parallel relationship of the vehicle's bed (or body) with the ground surface on which it rests.
For example, when a user of a pneumatic shock absorber applies a heavy load to the cargo carrying area of the vehicle, the vehicle body typically sinks onto the frame due to the weight of the load and the compression of the existing springs and shocks. The user simply injects a quantity of pressurized air to increase the length of the pneumatic shock and enable the vehicle body to be raised thereby overcoming the downward force associated with the load. In this manner, the vehicle may be leveled despite the load it carries.
Other such suspension systems incorporate a combination of shock absorbers and springs. For example, some light or heavy duty trucks incorporate a coil spring which surrounds the shock absorber. The coil spring adds the additional resistance to the displacement of the body when it is subject to heavy loads. Leaf springs are commonly associated with passenger vehicles and light duty trucks. A leaf spring is typically a series of stacked strips of long flexible metal. One end of the spring is attached to the body and the other is in some way attached to or in contact with the axle of the vehicle. The leaf spring applies an upward force on the body of the vehicle to compensate for applied loads in the passenger or cargo compartments.
Until now, however, a mechanical or electro-mechanical device suitable for leveling a motorized vehicle when it is subject to carrying a heavy load simply by rotating an adjustment collar has not been invented.